Described herein are device for transmitting and returning light and methods of manufacture and/or use found in the literature or practiced in the field. The literature is of interest for its teachings of the knowledge of skilled artisans at the time of this invention of device for transmitting and returning light and apparatuses for and methods of the manufacture thereof.
Specifically, U.S. Pat. No. 5,047,208 has an optical sensor for blood gas measurement with a pH sensitive absorption dye between the end of the fiber and the mirror. The mirror is located by a tube which carries the mirror spaced from and coaxially aligned with the fiber so the dye can be in the space.
U.S. Pat. No. 5,005,576 has an optical sensor for blood gas measurement capable of measuring pH, pO.sub.2 and pCO.sub.2 with light absorption dyes between the ends of the fibers and the mirrors. The mirrors are located in the distal end of the sheath with a silicone glue.
U.S. Pat. No. 5,047,627 has an optical sensor for blood gas measurement capable of measuring pH, pO.sub.2 and pCO.sub.2 with light absorption dyes between the ends of the fibers and the mirrors. The dye pellet for each fiber is attached with glue and mirrors are are not embedded in the fiber. Certainty and consistency of the optical coupling is not always repeat-able with adhesive attachment and optical efficiency is typically less than ideal. Moreover chemicals in the adherent may adversely influence the chemistry of the sensor and therefor accuracy.
U.S. Pat. No. 4,889,407 has an optical fiber with arrayed cells to substantially cover the cross sectional area of the fiber. An indicator sensitive to an analyte in a medium is used to determine pH and pCO2 in vivo in blood. That commonly assigned patent is incorporated herein by reference.